/**
 * The MIT License
 *
 * Copyright (c) 2010 Benjamin Klum
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package org.helgoboss.osgi_console_log_listener;


import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.service.log.LogEntry;
import org.osgi.service.log.LogListener;
import org.osgi.service.log.LogReaderService;
import org.osgi.util.tracker.ServiceTracker;

import java.io.PrintWriter;
import java.io.StringWriter;

public class OsgiConsoleLogListener implements LogListener, BundleActivator {

    private ServiceTracker logReaderTracker;

    public void logged(LogEntry log) {
        if (log.getMessage() != null) {
            StringBuilder sb = new StringBuilder();

            /* Print basic data */
            
            sb.append("[" + log.getTime() + ", " + log.getLevel() + ", " +
                    log.getBundle().getSymbolicName() + "] " + log.getMessage());


            /* Maybe print exception stacktrace */

            if (log.getException() != null) {
                sb.append("\nException Log:\n");
                StringWriter sw = new StringWriter();
                log.getException().printStackTrace(new PrintWriter(sw));
                sb.append(sw.toString());
            }

            System.out.println(sb.toString());
        }
    }

    /**
     * {@inheritDoc}
     */
    public void start(BundleContext context) throws Exception {
        logReaderTracker = new ServiceTracker(context, LogReaderService.class.getName(), null) {
            @Override
            public Object addingService(ServiceReference reference) {
                LogReaderService logReader = (LogReaderService) context.getService(reference);
                if (logReader != null) {
                    logReader.addLogListener(OsgiConsoleLogListener.this);
                }
                return logReader;
            }

            @Override
            public void removedService(ServiceReference reference, Object service) {
                LogReaderService logReader = (LogReaderService) service;
                if (logReader != null) {
                    logReader.removeLogListener(OsgiConsoleLogListener.this);
                }
                context.ungetService(reference);
            }
        };
        logReaderTracker.open();
    }

    /**
     * {@inheritDoc}
     */
    public void stop(BundleContext context) throws Exception {
        Object[] logReaders = logReaderTracker.getServices();
        if (logReaders != null) {
            for (Object obj : logReaders) {
                LogReaderService logReader = (LogReaderService) obj;
                logReader.removeLogListener(this);
            }
        }
        logReaderTracker.close();
    }


}
